[PATCH 7.1 054/228] Input: synaptics-rmi4 - block s_input when F54 queue is busy

7.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dmitry Torokhov <[email protected]>

commit fbfd76746adc16d64be29ff113f673b70bc3f5c2 upstream.

Changing the input (diagnostic report type) mid-stream changes the
report size. Since V4L2 buffers are allocated based on the size at
stream start, changing the input while streaming could lead to a
heap buffer overflow if the new size is larger than the allocated
buffers.

Prevent this by blocking VIDIOC_S_INPUT with -EBUSY if the V4L2 queue
is busy (streaming).

Fixes: 3a762dbd5347 ("[media] Input: synaptics-rmi4 - add support for F54 diagnostics")
Cc: [email protected]
Assisted-by: Antigravity:gemini-3.5-flash
Reviewed-by: Hans Verkuil <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Dmitry Torokhov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/input/rmi4/rmi_f54.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/input/rmi4/rmi_f54.c
+++ b/drivers/input/rmi4/rmi_f54.c
@@ -445,7 +445,12 @@ static int rmi_f54_set_input(struct f54_
 
 static int rmi_f54_vidioc_s_input(struct file *file, void *priv, unsigned int i)
 {
-	return rmi_f54_set_input(video_drvdata(file), i);
+	struct f54_data *f54 = video_drvdata(file);
+
+	if (vb2_is_busy(&f54->queue))
+		return -EBUSY;
+
+	return rmi_f54_set_input(f54, i);
 }
 
 static int rmi_f54_vidioc_g_input(struct file *file, void *priv,